In 1986, the U.S. Supreme Court ruled in Bowers v. Hardwick that anti-sodomy laws were permissible under the U.S. Constitution. Seventeen years later, in Lawrence v. Texas, the Supreme Court overruled that travesty of justice.

In 1993, the “don’t ask/don’t tell” policy was instituted. Seventeen years later, Congress is about to repeal another injustice against gay Americans.

I can’t believe this is actually going to happen. Just over a week ago, DADT repeal seemed dead. The Republicans had blocked it not once, but twice. Nancy Pelosi and Harry Reid and Joe Lieberman could have given up, but instead of just giving repeal their pro forma support and saying, “Sorry, we tried,” they actually worked to make it happen. A standalone bill seemed like a Hail Mary pass — there might not be enough time, and both the House and the Senate would have to pass it.

But it’s happening. At 3:00 p.m. today, the Senate will vote on the actual repeal bill, after 63 senators — including six Republicans — voted this morning to allow a simple majority up-or-down vote on repeal.

I don’t know if it’s significant that each of these mistakes — Bowers v. Hardwick and don’t ask/don’t tell — took the same amount of time, seventeen years, to reverse. Seventeen years is not quite a full generation, although it’s close: a gay person born in 1993 will be able to join the military as an openly gay American when he or she becomes a legal adult next year. Perhaps the seventeen-year time frame is just a coincidence.

What we do know is this: each step toward justice builds on the steps that came before. Before Lawrence v. Texas in 2003, being gay itself was practically a crime. In the 1990s, in a child custody case in Virginia, a judge ruled that a lesbian had no right to custody of her own child because Virginia’s anti-sodomy law made her a felon.

After Lawrence, such a ruling was no longer possible. Opponents of marriage equality can no longer use anti-sodomy laws to show that gay people are unfit to marry or raise children. A weapon in their arsenal was taken away.

And now the ban on gays in the military is about to be repealed. In and of itself, this is a wonderful thing and long overdue. But it will also give more ammunition to the fight for marriage equality. After all, how can you argue convincingly that someone who has served his or her country as a member of the U.S. military should not allowed to marry the person he or she loves, or is unfit to be a parent? We’ll see example after example of openly gay soldiers, sailors, Marines, and airmen and airwomen; we may not see tons of them right away, but we’ll begin to see more and more of them. Anti-gay bigots will start to see a mismatch between their own stereotyped preconceptions of gay people and the reality out there. A does not compute message will begin to form itself in their heads, and either they will change their minds or their heads will explode.

No victory stands alone. Each one is helped by previous victories and helps to create future victories. Our president likes to quote Dr. King: “The arc of the universe is long, but it bends towards justice.”

Each step nudges the trajectory a little bit more in the right direction.